Optical disc are in wide use which include compact discs having a diameter of 12 cm with audio signals recorded thereon (digital audio discs, hereinafter referred to as "CD"), video compact discs 12 cm in diameter and having recorded thereon audio signals and video signals as superposed on the signals (hereinafter referred to as "CDV"), and laser vision discs 20 cm or 30 cm in diameter and having recorded thereon audio signals and video signals as superposed on the signals (hereinafter referred to as "LD"). With CD and CVD, signals are recorded on only one side of the disc. LDs with a diameter of 20 cm include those having signals recorded on only one side thereof (hereinafter referred to as "LDS"), and those having signals recorded on both sides. Signals are recorded on both sides of LDs with a diameter of 30 cm.
In recent years, so-called convertible players have been proposed for playing these different kinds of discs with a single pickup (Unexamined Japanese Patent Publication SHO 58-212629, and "Television Techniques," published by Denshi Gijutsu Shuppan Co., Ltd., April 1986, pp. 25-33).
With such convertible players, the size of the disc clamped on the turntable is first detected by an optical sensor, and the disc thus identified is played by controlling the player according to the method specified for the disc, as by setting the disc drive motor to the specified speed.
The conventional convertible player is so adapted that the pickup reciprocatingly moves on the lower side of the disc in rotation to scan only the lower side of the disc, so that the disc, such as CD or CDV, with data recorded on only one side thereof must be placed on the turntable with the data recording side down. If the disc is placed with the other side down, the player is unable to read the data.
In such a case, it is necessary for the user to discharge the disc from the player, then turn the disc upside down and load the disc into the player again. This procedure is very cumbersome.